Weeds are not only unsightly, but they can also harm other nearby plants and flowers and can quickly consume even the best tended gardens. Some gardeners prefer to remove weeds by hand, but this process is time consuming and physically demanding work.

Some gardeners prefer to use weed killers which are a much more efficient way to rid your garden of common weeds as well as the more invasive ones. If you fall into this category, then this is the guide for you.

We’ve taken a good look at the best weed killers available and have tested each of them to find our favourite. Keep reading and learn which products will banish garden weeds for good.

Weed Killer Reviews

Weed Killer Buying Guide

Not all weed killers are the same. Some are designed to work on a specific species of weed whereas some are considered to be more of a general purpose weed killer. There are even differences in how each product neutralises weeds as well as a vast difference in the ingredients used to complete the task.

In this guide, we go into detail surrounding the different types of product available, how to use them and how they work as well as whether there are any safety concerns you’ll want to keep in mind.

How Do Weed Killers Work?

Each weed killer falls into a category and will help you to identify how they work. Some (systemic) weed killers are absorbed into the plant and travel down into the roots, effectively killing the weed from the inside.

Other (residual) weed killers are applied to the soil which then prevent species of weeds from germinating and ever appearing.

Contact weed killers are a type of herbicide that kill weeds on contact. Unfortunately, this type of product will often kill other species of plant too so should only be used in certain scenarios.

And selective weed killers can be applied in larger quantities (lawns) as they’re only effective on broadleaf weeds and are much safer for your garden.

Each product works in a very specific way to halt the growth of weeds. These methods are detailed below:

Preventing Photosynthesis

All plants need light to survive and produce food, a process known as photosynthesis. Some weed killers work by limiting the plants ability to photosynthesise. If a plant can’t produce food and energy, it essentially starves to death.

Preventing Protein Production

Like all living creatures the production of protein is an important element of plant growth and overall health. Some weed killers prevent a plant from being able to produce these necessary proteins which eventually causes the plant to die. Glyphosate, the active ingredient and chemical you’ll find in Roundup weed killer works in this way.

Manipulating Hormones

Plants have hormones too, and these chemical hormones are linked to natural growth. Some weed killers contain plant hormones, some natural and some synthetic such as 2,4-D (Trimec). When these products are applied to the plant, the hormone is absorbed and confuses the plant’s own growth system. This leads to growth deformities before eventual death.

Additional Information

It’s important to remember that different types of weed killer target different types of plant. Some are designed to kill only broadleaf weeds such as dandelions, whereas others might target grasses.

As mentioned, some target all types of plant. For pet owners out there, there is no such thing as a “dog-friendly weed killer”. You will need to allow the product to dry completely before allowing your dog anywhere near the application site. Finally, always read the label for safety information and application instructions. Strong weed killers are more effective but can be more dangerous.

Types of Weed Killers

Selective weed killers are usually safe for application on lawns and will only target specific types of plant. Non-selective weed killers will kill any plant they come into contact with.

Systemic weed killers are slower to work than others but can kill even the most resistant plants like brambles and briars. Note that systemic weed killers are sometimes called industrial weed killers. Post-emergence weed killers are designed to be applied to the weed after sprouting, while pre-emergence weed killers (also known as residual) are applied to soil before growth begins.

There are also some products on the market referred to as “natural” weed killers. Corn gluten is one ingredient which you’ll find used in some selective, pre-emergent weed killers. Corn naturally secretes a chemical that kills other nearby plants. That chemical is found in significant concentrations in corn gluten. However, it is generally not effective against common lawn grasses which is what makes it a great option for pre-emergent weed control in lawns.

The last type is an industrial weed killer also known as “soil sterilisers”. These products are uncommon and are rarely sold in the UK. If you do come across these products, we suggest you steer clear. They are designed to kill everything in the area and will remain in soil for several years. These chemicals can also easily find their way into nearby water courses which can devastate any water-based ecosystem.

General Weed Control

Prevention Is the Best Cure

Weeds are annoying at best and harmful at worst. That’s why it’s a good idea to keep on top of their growth to prevent total colonisation of your garden. This is a continuous process so consider opting for a weed killer that prevents them from ever appearing in the first place.

Consider Mulching

Spreading a thick layer of organic mulch can limit the growth of weeds. Doing so helps soil retain moisture as well as smothers small weeds. Decomposed mulch will also add nutrients to the soil and prevent sunlight from reaching the weeds.

Use a Thick Weed Control Fabric

Weed control fabric can prevent weeds from growing. This is a product that can be effectively used under patios, paths, walkways and garden decking. Once laid, these fabrics prevent weeds from growing through. Cost effective and easy to use.

Don’t Leave Soil Unplanted

Weeds can thrive in open spaces where nothing is growing as they have less competition for nutrients. Plant your flowers and vegetables close together to prevent weeds from growing in gaps and make sure all soiled area is planted.

Fertilise Soil Regularly

Fertilising your garden will keep it healthy and increase the strength of your plants and flowers. This will make it much harder for invasive weeds to take hold as there’ll be a dense root system preventing them from germinating properly.

Final Verdict

The type of weed killer you need is down to the type of garden you have. We’ve tested the best from each category, so simply choose based on your preferences and requirements.

If in doubt, our top recommendation will serve you well and is the weed killer we would recommend for most gardeners.